1. Field of the Invention
The present invention relates generally to the field of preventing injury to the operators of machinery which includes a hose through which fluid is pumped under high pressure. More specifically, and in the preferred e embodiment, the invention relates to the protection of operators of high pressure and high velocity sewer cleaning equipment which uses water jeeting of the cleaning of sewer laterals.
2. Description of the Prior Art
Several types of sewer and catch basin cleaning machines are available on the market. Two types of such machines are manufactured by the assignee of the present invention, including the CAMEL.RTM. machines (which include sewer and catch basin cleaning compounds and the "CAMEL JET".RTM. machines which are principally used for sewer cleaning without catch basin vacuuming.
In both types of machines, a hose reel is provided for containing up to 800 feet or more of a hose through which water is pumped at high pressure during the sewer cleaning operation. Pressures as high as 2500 psi or more are utilized with a jetting nozzle having reverse nozzle openings which, in effect, drive the nozzle into the sewer lateral pulling hose behind. The nozzles create a cutting a nd loosening action within the sewer laterals also that debris is loosened and carried by water flow to a catch basin or manhole. In those machines which include vacuum systems, a vacuumhose supported by a hydraulic boom, removes material, including material ial loosened from the laterals, into a debris tank on the truck A machine of this nature is disclosed in the Wurster, et al U.S. Letters Pat. No. 4,134,174 entitled "Sewer And Catch Basin Cleaner", issued on Jan. 16, 1979. This patent also discloses machines which include water filtration systems to allow purification of the water collected in the debris tank for subsequent reuse in the water jetting operation
The hose reel in the aforementioned type of equipment may be mounted within an open area behind the truck cab or in front of the truck, depending on the desired end use for the machine In both cases, the hose reels are hydraulically driven to wind the hose onto the reel after the jetting forces have unwound the hose. Pulling the hose against the pressure of the jetting nozzle adds to the effectiveness of the lateral cleaning operation
Another type of machine is the "CAMEL JET" machine which does not include the vacuum system, but does include the hose reel and high pressure jetting equipment described above In this particular machine, the hose reel is mounted with its axis perpendicular to the axis of the truck and aligned so that the hose is unwound at the rear of the truck or trailer body. It should be understood that the reel may also be positioned in front of the chassis if desired A lever, known as a level winder, is provided for steering the hose during rewinding to prevent the hose wraps from snarling on the reel and further to assist in aligning the hose with the entrance to a catch basin or manhole and into a sewer:lateral.
One of the significant problems associated with the use of this type of equipment is the potential for operator injury in the event the high pressure hose or its coupling were to burst or come loose during use. Concerning the latter situation, newly supplied hoses are continuous, without interruption throughout their
However, it is a common practice to utilize repair couplings in areas where a hose becomes abraded or is cut or otherwise damaged The hoses are repaired by severing to remove the damaged area and are reconnected with the use of repair couplings
An operator should advantageously stand relatively close to the reel and catch basin or manhole for normal operation, because he must look into the manhole for guiding the hose into the sewer lateral. Visibility into the catch basin or manhole is particularly vital during the initial set up and during retrieval of the high pressure hose. The safety problem arises if the hose were to burst or a coupling were to fail at the area between the hose reel and the location where the hose enters the manhole. Here, the end of the hose can fly wildly about under the high water pressure, creating risk of injury.
The general problem has been recognized since at least 1984 by the assignee of the present invention, and as illustrated in one of its brochures published about that time, a transparent shield was provided around the upper one-quarter of the hose reel in the general vicinity of where an operator would stand.
Other types of high velocity sewer flushing machines are made by Sreco as described in its product bulletins 3000 and 3045. The latter product bulletin describes the SAFE-WAY.RTM. machine, which includes a cabinet extending from the gear of the truck in the vicinity of the hose reel. The cabinet includes components which are assembled on site for each job, and a clear shatter-proof view window is included so that the hose can be seen from the control panel area. The cabinet is spaced above the roadway so that the hose can be seen below the level of the cabinet, several inches above the manhole rim. The device is relatively cumbersome to use, and the need to disassemble and reassemble the cabinet presents a serious obstacle to machine efficiency The Sreco machines must be used on a relatively level surface and little or no room is available for entry of a vacuum hose. It is necessary to use mirrors (not shown in the product bulletins) to see into the manhole and during operation the pressure hose may be located very close to the operator with a portion exposed between the lowermost part of the shield and the street level
Another device providing shielding for a portion of a high pressure hose is shown in an advertisement of Underground, Inc. A catch basin or manhole cleaner is supported by a mobile trailer While protection is provided near the reel, no protection is provided between the lowermost marginal edge of the shielding housing and the catch basin or manhole.
A containment system which would prevent operator injury and permit hose manipulation and easy access to the hose reel and which otherwise overcomes the shortcomings of the devices of the prior art would represent a significant advance in this technology.
In co-pending, commonly assigned U.S. Pat. application Ser. No. 07/340,899 filed on Apr. 17, 1989, and now Pat. No. 4,944,258, an operator protection system which overcomes some of these problems is described. The system disclosed in such application includes an upper, hood-like shield substantially enclosing the hose reel. A flexible, tubular second enclosure extends from within the first enclosure down into the manhole. The hose is passed through the tubular enclosure into the lateral and is guided by the operator in a conventional manner. Head-to-toe protection is provided by this system if properly used.
Several problems remain with regard to the efficient use of operator protection systems as exemplified by the earlier application, namely, methods to ensure the use of the system as furnished by the manufacturer and gaining access to the hose reel or other internal components of the machine in a safe manner. To expedite operation of the machinery described in the commonly-owned application, the operator could, contrary to the instructions provided with the equipment, raise the first enclosure to gain access to the internal mechanisms or hose reel and turn on the machinery whereby water would be forced under high pressure through the hose. Furthermore, it is somewhat cumbersome with the prior device to gain access, while the machinery is shut down, to the hose wrappings or to insert the sewer jetting nozzle into a containment tube or into a water recirculation system if such is provided The latter system is one in which fluid is circulated continually through the water tank and hoses in cold weather to prevent freezing thereof An invention which overcomes these situations would represent yet another significant advance in this technology.